DNA methylation is catalyzed by DNMT1, DNMT3a, and DNMT3b. Furthermore, histone deacetylation is catalyzed by HDACs. Therefore, DNMTs and HDACs induce hypermethylation and histone deacetylation respectively resulting in TSGs transcriptional repression and cancer induction (Li et al., 2007). This evidence concerns the gene DNMT1 and cancer.